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Preambles from any set of transmissions, on one real microsecond axis. Overhead stops being a number in a table and becomes a length.

Pick whatever you want to compare, using the same browser and the same facets as the frames page. The page says what is varying rather than restricting combinations — comparing two things at once is a fair thing to do as long as you know that is what you are doing.

payload break the data field rate

How the data field is worked out

A data field's duration cannot be known without choosing a payload size and a rate, so the controls above ask for both rather than inventing them. Given those, the arithmetic is exact:

N_SYM = ⌈(SERVICE + 8·length + TAIL) ÷ bits per symbol⌉ · T_DATA = N_SYM × symbol duration

The ceiling is the interesting part. Airtime moves in whole symbols, so one extra octet costs either a full symbol or nothing at all — which is why the totals step rather than slide as you drag the payload. 802.11b has no symbol to round up to and is continuous.

Bits per symbol come from each PHY's own bundle, cited and unverified like everything else here, for 20 MHz and one spatial stream. Wider channels and more streams carry more per symbol; those variants are not authored yet, and neither are short guard intervals. The variable training fields — HE-LTF and friends — are still nominal, since they grow with the stream count.

What is still not drawn

The axis fits whatever is selected. Every row shares one axis at any moment — that is what makes the bars comparable — and the axis itself rescales as you tick rows, with real microseconds marked against it. Tick 802.11b to see why: its 192 µs preamble needs an axis ten times the one an 802.11a frame needs.